Ink jet printers operate by using ink ejectors that eject small droplets of liquid ink onto print media according to a predetermined pattern. In some implementations, the ink is ejected directly on a final print media, such as paper. In some implementations, the ink is ejected on an intermediate print media, e.g. a print drum, and is then transferred from the intermediate print media to the final print media. Some ink jet printers use cartridges of liquid ink to supply the ink jets. The solid ink is melted in a page-width print head, which jets the molten ink in a page-width pattern onto an intermediate drum. The pattern on the intermediate drum is transferred onto paper through a pressure nip.
Ink that flows through the print head may contain debris in the form of particles of various sizes and compositions. This debris may clog an inlet, an outlet, an aperture or other manifolds and channels within the print head. This can result in weak, missing or intermittent jetting that can cause undesirable printing defects. To address this issue, filters have been included in the print head. Though effective at removing debris, the small pore size of these filters requires large pressure drops to force the ink through the filters and ensure the required throughput. For gravity driven loaders, the pressure drop across the filter is fixed by the height of the film wetting the filter. Because the driving force of gravity driven loaders is hydrostatic pressure, throughput of the ink jet printer can be limited due to the pressure drop caused by the filters.